MY OIL LIGHT IS ON WHEN OIL SHOWS FULL. WHAT COULD BE THE PROBLEM?

1997 Plymouth Neon • 106 miles

I have a 1997 Plymouth Neon. It has about 106,000 miles on it. I just had the cylinder head replaced about 200 miles ago. The oil light has come on recently. I checked the oil to see if oil had to be added. I added a quart of oil and the light went off, but then immediately came on again. The engine was not making any noise as far as knocking or pinging as if there was no oil. What could be wrong?